java基础 - 补充

1.  8 * 2 运行最快的计算方式

8<<1

 

2.int a = 1; int b = 3; 交换ab的值

int c = a;
a= b;
b =c;

a = a + b; //1 + 3 = 4
b = a - b;  //4 - 3 = 1
a = a - b;  //4 - 1 = 3

a = a ^ b; // 1 ^ 11 = 10 = 2
b = a ^ b; // 10 ^ 11 = 1 = 1
a = a ^ b; // 10 ^ 1 = 11 = 3
//原理是利用了  a ^ b ^ b = a异或两次等于自己

转载于:https://www.cnblogs.com/clamp7724/p/11568848.html